Multi-band, dual-polarization reflector antenna

ABSTRACT

An antenna includes a reflector and a waveguide assembly. The waveguide assembly includes a feed assembly and a support member that extends from behind the reflector to orient the feed assembly for direct illumination of the reflector. The waveguide assembly includes a first waveguide coupled to a first portion of a common waveguide, a second waveguide coupled to a second portion of the common waveguide, and a septum layer that includes a septum polarizer coupled between the common waveguide and the first and second waveguides.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application and, pursuant to 35U.S.C. § 120, is entitled to and claims the benefit of earlier filedapplication U.S. application Ser. No. 15/059,214 filed Mar. 2, 2016, thecontent of which is incorporated herein by reference in its entirety forall purposes.

BACKGROUND

Unless otherwise indicated, the foregoing is not admitted to be priorart to the claims recited herein and should not be construed as such.

Antenna systems can include multiple antennas in order to provideoperation at multiple frequency bands. For example, in mobileapplications where a user moves between coverage areas of differentsatellites operating at different frequency bands, each of the antennasmay be used to individually communicate with one of the satellites.However, in some applications such as on an airplane, performancerequirements and constraints such as size, cost and/or weight, maypreclude the use of multiple antennas. Antennas for mobile applicationsmay be reflector type antennas of a similar or common range of sizes andthe reflector portion of the antenna system is itself a wideband elementof the antenna and suitable for operation at multiple frequency bands.

SUMMARY

In some embodiments according to the present disclosure, an antenna mayinclude a single reflector and a waveguide assembly. The waveguideassembly may include a feed assembly and a support member that extendsfrom behind the reflector to orient the feed assembly for directillumination of the reflector. The waveguide assembly may include afirst housing layer having a first waveguide coupled to a first portionof a common waveguide, a second housing layer having a second waveguidecoupled to a second portion of the common waveguide, and a septum layerbetween the first housing layer and the second housing layer. The septumlayer may include a septum polarizer coupled between the commonwaveguide and the pair of waveguides.

The following detailed description and accompanying drawings provide abetter understanding of the nature and advantages of the presentdisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

With respect to the discussion to follow and in particular to thedrawings, it is stressed that the particulars shown represent examplesfor purposes of illustrative discussion, and are presented in the causeof providing a description of principles and conceptual aspects of thepresent disclosure. In this regard, no attempt is made to showimplementation details beyond what is needed for a fundamentalunderstanding of the present disclosure. The discussion to follow, inconjunction with the drawings, makes apparent to those of skill in theart how embodiments in accordance with the present disclosure may bepracticed. In the accompanying drawings:

FIG. 1 is a diagram of a satellite communication system in which anantenna as described herein can be used.

FIG. 2 is a block diagram of an example antenna.

FIG. 3 is a more detailed block diagram of the example antenna of FIG.2.

FIG. 4 illustrates a perspective view of an example antenna.

FIGS. 5A and 5B illustrate different views of an example antenna.

FIGS. 6A and 6B illustrate different expanded views of an example feedassembly and support structure for an antenna.

FIGS. 7A and 7B illustrate perspective and side views of an example feedassembly.

FIGS. 8A and 8B illustrate side and perspective views of an example feedassembly.

FIG. 9 illustrates beam pointing directions of an example antenna.

FIGS. 10, 11A, 11B, and 11C present illustrative examples of waveguidesin accordance with the present disclosure.

DETAILED DESCRIPTION

In the following description, for purposes of explanation, numerousexamples and specific details are set forth in order to provide athorough understanding of the present disclosure. It will be evident,however, to one skilled in the art that the present disclosure asexpressed in the claims may include some or all of the features in theseexamples, alone or in combination with other features described below,and may further include modifications and equivalents of the featuresand concepts described herein.

FIG. 1 shows a diagram of a satellite communication system 100 inaccordance with various aspects of the present disclosure. The satellitecommunication system 100 includes a first satellite 105-a, a firstgateway 115-a, a first gateway antenna system 110-a, and an aircraft130. The first gateway 115-a communicates with at least a first network120 a. In operation, the satellite communication system 100 can providefor one-way or two-way communications between the aircraft 130 and thefirst network 120-a through at least the first satellite 105-a and thefirst gateway 115-a.

In some examples, the satellite communications system 100 includes asecond satellite 105-b, a second gateway 115-b, and a second gatewayantenna system 110-b. The second gateway 115-b may communicate with atleast a second network 120-b. In operation, the satellite communicationsystem 100 can provide for one-way or two-way communications between theaircraft 130 and the second network 120-b through at least the secondsatellite 105-b and the second gateway 115-b.

The first satellite 105-a and the second satellite 105-b may be anysuitable type of communication satellite. In some examples, at least oneof the first satellite 105-a and the second satellite 105-b may be in ageostationary orbit. In other examples, any appropriate orbit (e.g., lowearth orbit (LEO), medium earth orbit (MEO), etc.) for the firstsatellite 105-a and/or the second satellite 105-b may be used. The firstsatellite 105-a and/or the second satellite 105-b may be a multi-beamsatellite configured to provide service for multiple service beamcoverage areas in a predefined geographical service area. In someexamples, the first satellite 105-a and the second satellite 105-b mayprovide service in non-overlapping coverage areas, partially-overlappingcoverage areas, or fully-overlapping coverage areas. In some examples,the satellite communication system 100 includes more than two satellites105.

The first gateway antenna system 110-a may be one-way or two-way capableand designed with adequate transmit power and receive sensitivity tocommunicate reliably with the first satellite 105-a. The first satellite105-a may communicate with the first gateway antenna system 110-a bysending and receiving signals through one or more beams 160-a. The firstgateway 115-a sends and receives signals to and from the first satellite105-a using the first gateway antenna system 110-a. The first gateway115-a is connected to the first network 120-a. The first network 120-amay include a local area network (LAN), metropolitan area network (MAN),wide area network (WAN), or any other suitable public or private networkand may be connected to other communications networks such as theInternet, telephony networks (e.g., Public Switched Telephone Network(PSTN), etc.), and the like.

Examples of satellite communications system 100 may include the secondsatellite 105-b, along with either unique or shared associated systemcomponents. For example, the second gateway antenna system 110-b may beone-way or two-way capable and designed with adequate transmit power andreceive sensitivity to communicate reliably with the second satellite105 b. The second satellite 105-b may communicate with the secondgateway antenna system 110-b by sending and receiving signals throughone or more beams 160-b. The second gateway 115-b sends and receivessignals to and from the second satellite 105-b using the second gatewayantenna system 110-b. The second gateway 115-b is connected to thesecond network 120-b. The second network 120-b may include a local areanetwork (LAN), metropolitan area network (MAN), wide area network (WAN),or any other suitable public or private network and may be connected toother communications networks such as the Internet, telephony networks(e.g., Public Switched Telephone Network (PSTN), etc.), and the like.

In various examples, the first network 120-a and the second network120-b may be different networks, or the same network 120. In variousexamples, the first gateway 115-a and the second gateway 115-b may bedifferent gateways, or the same gateway 115. In various examples, thefirst gateway antenna system 110-a and the second gateway antenna system110-b may be different gateway antenna systems, or the same gatewayantenna system 110.

The aircraft 130 can employ a communication system including amulti-band antenna 140 described herein. The multi-band antenna 140 caninclude a multi-band feed assembly oriented to illuminate a reflector143. In the illustrated example, the multi-band feed assembly includes afirst feed 142 and a second feed 142. Alternatively, the number of feedsin the multi-band feed assembly may be greater than two. In someexamples, the first feed 141 and/or the second feed 142 can be a dualpolarized feeds. The antenna 140 can be mounted on the outside of theaircraft 130 under a radome (not shown). The antenna 140 may be mountedto an antenna assembly positioning system (not shown) used to point theantenna 140 to a satellite 105 (e.g., actively tracking) duringoperation. In some examples, antenna assembly positioning system caninclude both a system to control an azimuth orientation of an antenna,and a system to control an elevation orientation of an antenna.

The first feed 141 may be operable over a different frequency band thanthe second feed 142. The first feed 141 and/or the second feed 142 mayoperate in the International Telecommunications Union (ITU) Ku, K, orKa-bands, for example from approximately 17 to 31 Giga-Hertz (GHz).Alternatively, the first feed 141 and/or the second feed 142 may operatein other frequency bands such as C-band, X-band, S-band, L-band, and thelike. In a particular example, the first feed 141 can be configured tooperate at Ku-band (e.g. receiving signals between 10.95 and 12.75 GHz,and transmitting signals between 14.0 to 14.5 GHz), and the second feed142 can be configured to operate at Ka-band (e.g. receiving signalsbetween 17.7 and 21.2 GHz, and transmitting signals between 27.5 to 31.0GHz). In some examples, the multi-band antenna 140 may include a thirdfeed (not shown). The third feed may for example operate at Q-bandtransmitting signals between 43.5 to 45.5 GHz and operating inconjunction with the military frequency band segment of Ka-band between20.2 to 21.2 GHz. However, in the Ka/Q-band operational mode the antennawill need to be oriented towards the satellite with a compromise beampointing condition for the Ka-band beam and the Q-band beam.Alternatively the third feed can be configured to operate at V-bandreceiving signals between 71 to 76 GHz and W-band transmitting signalsbetween 81 to 86 GHz with a single beam position for V/W-band operation.

In some examples of the satellite communications system 100, the firstfeed 141 can be associated with the first satellite 105-a, and thesecond feed 142 can be associated with the second satellite 105-b. Inoperation, the aircraft 130 can have a location that is within acoverage area of the first satellite 105-a and/or within a coverage areaof the second satellite 105-b, and communications using either the firstfeed 141 or the second feed 142 can be selected based at least in parton the position of the aircraft 130. For instance, in a first mode ofoperation, while the aircraft 130 is located within a coverage area ofthe first satellite 105-a, the antenna 140 can use the first feed 141 tocommunicate with the first satellite 105-a over one or more first beams151. In the first mode of operation, the second feed 142 and associatedelectronics can be in an inactive state without maintaining acommunications link with a satellite. In a second mode of operation,while the aircraft 130 is located within a coverage area of the secondsatellite 105-b, the antenna 140 can use the second feed 142 tocommunicate with the second satellite 105-b over one or more secondbeams 152-b. The second mode can be selected, for instance, in responseto the aircraft 130 entering a coverage area of the second satellite105-b, and/or leaving a coverage area of the first satellite 105-a. Inexamples where the aircraft is located within an overlapping coveragearea of both the first satellite 105-a and the second satellite 105-b,the second mode can be selected based on other factors, such as networkavailability, communication capacity, communication costs, signalstrength, signal quality, and the like. In the second mode of operation,the first feed 141 and associated electronics can be in an inactivestate without maintaining a communications link with a satellite.

In other examples of the satellite communications system 100, the firstfeed 141 and the second feed 142 can both be associated with the firstsatellite 105-a. In the first mode of operation the antenna 140 can usethe first feed 141 to communicate with the first satellite 105-a overone or more first beams 151, and in an alternate example of the secondmode of operation, the antenna 140 can use the second feed 142 tocommunicate with the first satellite 105-a over one or more second beams152-a. The alternate example of the second mode can be selected tochange from a first frequency band and/or communications protocolassociated with the first feed 141 to a second frequency band and/orcommunications protocol associated with the second feed 142.

The communication system of the aircraft 130 can provide communicationservices for communication devices within the aircraft 130 via a modem(not shown). Communication devices may utilize the modem to connect toand access at least one of the first network 120-a or the second network120-b via the antenna 140. For example, mobile devices may communicatewith at least one of the first network 120-a or the second network 120-bvia network connections to modem, which may be wired or wireless. Awireless connection may be, for example, of a wireless local areanetwork (WLAN) technology such as IEEE 802.11 (Wi-Fi), or other wirelesscommunication technology.

The size of the antenna 140 may directly impact the size of the radome,for which a low profile may be desired. In other examples, other typesof housings are used with the antenna 140. Additionally, the antenna 140may be used in other applications besides onboard the aircraft 130, suchas onboard boats, automobiles or other vehicles, or on ground-basedstationary systems.

FIG. 2 is a block diagram of an example antenna 200. Antenna 200 maycomprise a reflector 202 to transmit and receive signals, for example,with a satellite (e.g., 105, FIG. 1). Signal handling components in theantenna 200 may include a multi-band feed assembly 204, a waveguidesection 206, and a radio frequency (RF) section 208. As described inmore detail below, the multi-band feed assembly 204 includes multiplefeeds operable over different frequency bands. In embodiments describedherein, the reflector 202 is the only reflector of the antenna 200. Inother words, antenna 200 has single reflector 202, such that the feedsof the multi-band assembly 204 directly illuminate the single reflector202. For discussion purposes going forward, each feed of the multi-bandfeed assembly 204 may be described as a dual-circularly polarized feed.More generally, a feed may be dual-linearly polarized, dual-circularlypolarized, etc. The antenna 200 may include components to position theantenna 200. In some embodiments, for example, the positioningcomponents may include a motor controller 210, an azimuth motor 212 torotate the pointing direction of antenna 200 along the azimuth, and anelevation motor 214 to rotate the angle of elevation of antenna 200.

The antenna 200 may be used in any suitable communications system. In aparticular embodiment, for example, the antenna 200 may be provisionedin an aircraft system 20. The R/F section 208 may receive communicationsfrom the aircraft system 20 for transmission by the antenna 200, and mayprovide received communications to the aircraft system 20. Similarly,the antenna 200 may receive positioning information from the aircraftsystems 20 to point the antenna 200.

FIG. 3 is a more detailed block diagram of the antenna 200 of FIG. 2. Inaccordance with some embodiments of the present disclosure, for example,the multi-band feed assembly 204 may comprise a first feed 302 and asecond feed 304. In some embodiments, the first and second feeds 302,304 may be offset feeds. In other words, the first and second feeds 302,304 may not be aligned along the central axis 202 a of reflector 202,but rather may be offset from the axis 202 a. Although two feeds 302,304 are shown, embodiments in accordance with the present disclosure mayinclude more than two feeds.

In some embodiments, the first feed 302 may transmit and receive signalsin a first frequency band. In a particular embodiment, for example, thefirst feed 302 may operate in the Ku band. In some embodiments, thesecond feed 304 may transmit and receive signals in a second frequencyband different from the first frequency band. In a particularembodiment, for example, the second prime focus feed 304 may operate inthe Ka band. Additional details of the first and second feeds 302, 304will be discussed in more detail below. Embodiments in accordance withthe present disclosure may operate in multiple (two or more) frequencybands. However, for discussion purposes going forward, dual bandoperation of the first and second feeds 302, 304 in the Ku and Ka bands,respectively, may be described without loss of generality.

In some embodiments, the waveguide section 206 may include a system ofwaveguides that couple or otherwise connect the RF section 208 with themulti-band feed assembly 204. In some embodiments, such as shown in FIG.3 for example, the waveguide section 206 may include waveguides 312R,312L coupled between the RF section 208 and the first feed 302 to guidesignals (to be transmitted or received) in the Ku band between the RFsection 208 and the first feed 302. In some embodiments, for example,waveguide 312R may be a diplexer that carries right-hand circularlypolarized signals (right-hand circular polarization, RHCP) in the Kuband. Likewise in some embodiments, waveguide 312L may be a diplexerthat carries left-hand circular polarization (LHCP) in the Ku band.

The waveguide section 206 may further include waveguides 314R, 314Lcoupled between the RF section 208 and the second feed 304 to guidesignals in the Ka band between the RF section 208 and the second feed304. In some embodiments, for example, waveguide 314R may be a diplexerthat carries right-hand circular polarization in the Ka band, andwaveguide 314L may be a diplexer that carries left-hand circularpolarization in the Ka band.

In a particular embodiment, the waveguides 312R, 312L, 314R, 314L may bearranged in two subassemblies 306R, 306L. The subassembly 306R,comprising the waveguide 312R (Ku band) and the waveguide 314R (Kaband), may be a diplexer assembly configured to guide right-handcircularly polarized signals. Likewise, subassembly 306L, comprising thewaveguide 312L (Ku band) and the waveguide 314L (Ka band), may be adiplexer assembly to guide left-hand circularly polarized signals. Inalternative embodiments, the waveguides 312R, 312L, 314R, 314L can bearranged in other configurations.

The RF section 208 may include interfaces 322, 324 to communicate with abackend communication system (e.g., aircraft system 20, FIG. 2) toreceive communications for transmission by antenna 200 and to providecommunications received by the antenna 200. In some embodiments, forexample, interface 322 may be configured to provide and receive Kaband-type communications with the backend communication system.Interfaces 324 likewise, may provide and receive Ku band-typecommunications with the backend communication system.

The RF section 208 may further include a transceiver 332 to supporttransmission and reception of signals in the Ka band. In someembodiments, for example, the transceiver 332 may include an input portcoupled to diplexer 314R to receive right-hand circularly polarizedsignals from antenna 200. The transceiver 332 may include another inputcoupled to diplexer 314L to receive left-hand circularly polarizedsignals from antenna 200. The transceiver 332 may process the receivedsignals (e.g., filter, amplify, downconvert) to produce a return signalthat can be provided via interface 322 to the backend communicationsystem.

The transceiver 332 may process (e.g., upconvert, amplify)communications received from the backend communication system to producesignals for transmission by antenna 200. In some embodiments, forexample, the transceiver 332 may generate right-hand and left-handcircularly polarized signals at its output ports. The output ports maybe coupled to diplexers 314R and 314L to provide the amplified signalsfor transmission by antenna 200.

The RF section 208 may further include a transceiver 342 to supporttransmission and reception of signals in the Ku band. In someembodiments, for example, the transceiver 342 may include an input portcoupled to diplexer 312R to receive right-hand circularly polarizedsignals received by antenna 200. Another input port may be coupled todiplexer 312L to receive left-hand circularly polarized signals receivedby antenna 200. The transceiver 342 may process the received signals(e.g., filter, amplify, downconvert) to produce a return signal that canbe provided via interface 326 to the backend communication system.

The transceiver 342 may process (e.g., upconvert, amplify)communications received via interface 324 from the backend communicationsystem to produce signals for transmission by antenna 200. In someembodiments, the transceiver 342 may generate right-hand and left-handcircularly polarized transmit signals at output ports coupled todiplexers 312R and 312L for transmission by antenna 200.

FIG. 4 illustrates a perspective view of an example antenna 400. Theantenna 400 may include a reflector 402. In some embodiments, thereflector 402 may be a parabolic reflector. In a particular design, forexample, the reflector 402 may have a diameter D of about 11.45″. Thefocal length F may be selected to achieve an F/D ratio of about 0.32. Itwill be appreciated that these parameters will be different fordifferent designs.

In various embodiments, the reflector 402 may have any spherical,aspherical, bi-focal, or offset concave shaped profile necessary for thegeneration of desired transmission and receiving beams. In theillustrated embodiment, the reflector 402 is the single reflector of theantenna 400, such that multi-band feed assembly 400 directly illuminatesthe reflector 402. In some embodiments, the reflector 402 may be used inconjunction with one or more additional reflectors in a system ofreflectors (not shown). The system of reflectors may be comprised of oneor more profiles such as parabolic, spherical, ellipsoidal, or othershaped profile, and may be arranged in classical microwave opticalarrangements such as Cassegrain, Gregorian, Dragonian, offset, side-fed,front-fed, or other similarly configured arrangements. The reflector 402may also be substituted with other types of directly illuminatedfocusing apertures. In an alternate embodiment, the multi-band feedassembly 400 directly illuminates a lens aperture (not shown). The useof reflective or transmissive microwave optics as dual or complementaryfocusing aperture systems may also be used.

The antenna 400 may include a multi-band feed assembly 404. In theparticular embodiment shown in FIG. 4, for example, the multi-band feedassembly 404 is configured as a prime focus feed. In other words, thefeed assembly 404 may be positioned in front of the reflector 402 todirectly illuminate the reflector 402 and aligned along an axis (centralaxis) 402 a of the reflector 402. As will be explained in more detailbelow, in accordance with the some embodiments of the presentdisclosure, the feed assembly 404 may have a dual feed constructioncomprising feeds 502, 504 (FIG. 6A) that are offset from the reflectoraxis 402 a. Accordingly, the feed assembly 404 may be regarded as aprime focus offset feed assembly.

A support member (waveguide spar) 414 may be coupled to or otherwiseintegrated with the feed assembly 404 to provide support for the feedassembly 404. In accordance with the present disclosure, the supportmember 414 may also serve as a waveguide to propagate signals to andfrom the feed assembly 404. In accordance with some embodiments of thepresent disclosure, the support member 414 may extend through an opening402 b formed at the periphery of reflector 402. In a particularembodiment, the support member 414 may have an arcuate shape that passesthrough opening 402 b of reflector 402 and toward reflector axis 402 a.The support member 414 may include one or more features (discussed inmore detail below with respect to FIGS. 6A-6B) for minimizing thescattering interaction between the reflector 402 and support member 414.Similar treatment (not shown) may be included to behave as a transitionon the opposite surface (outboard) side of the support member in theform of a shape taper. Such an arrangement can reduce the swept volumeof the antenna 400 as compared to extending the support member 414around the periphery of the reflector 402. The combination of feedassembly 404 and support member 414 may constitute a waveguide assembly500, discussed in more detail below in connection with FIGS. 5A and 5B.

In accordance with the present disclosure, the antenna 400 may includean RF & waveguide package 412 mounted on or otherwise affixed adjacentthe rear side of the reflector 402. The RF & waveguide package 412 mayinclude an RF section 408. In some embodiments, for example, the RFsection 408 may include a first transceiver module 482 (e.g., Kutransceiver module 342, FIG. 3), a power amplifier module 484, and asecond transceiver module 486 (e.g., Ka transceiver 332, FIG. 3). Inaccordance with the present disclosure, the RF & waveguide package 412may further include waveguide components 406 that couple the modules ofthe RF section 408 with the feed assembly 404, in conjunction with thesupport member 414.

FIG. 5A shows a side view of antenna 400, illustrating the compactpackaging design of the RF & waveguide package 412 in accordance withthe present disclosure. In order to achieve a low profile packagingdesign, the respective circuitry for each module in the RF section 408(e.g., first transceiver module 482, power amplifier module 484, secondtransceiver module 486) may be laid out on a single printed circuitboard (PCB, not shown). Likewise, the waveguide components 406 mayinclude waveguides (shown below) having a low-profile design to provideconnectivity between the modules in the RF section 408 and the feedassembly 404, and fits within a package outline 412 a of the RF &waveguide package 412. Examples of such waveguides are described below.

Referring to FIG. 5B, the combined volume of space swept out by antenna400 when it is rotated about all it axes of rotation (e.g., azimuthalaxis, elevational axis, etc.) establishes a sweep volume (or sweptvolume) of the antenna 400. Likewise, the reflector 402 may define afirst swept volume 422 when rotated about an azimuth axis and a secondswept volume 424 when rotated about an elevation axis. The combinationof the first and second swept volumes 422, 424 shown in FIG. 5B mayestablish a sweep volume of reflector 402. The sweep volume of reflector402 may have a spherical shaped volume, and in general may be any shapedepending on the number of axes of rotation and the relative location ofthe axes of rotation. In accordance with the present disclosure, the RF& waveguide package 412 may have a compact form factor that fits withinthe sweep volume (e.g., defined by sweep volumes 422, 424) of thereflector 402. FIG. 5B, for example, shows that the package outline 412a of the RF & waveguide package 412 fits within the sweep volumes 422,424 of reflector 402.

FIGS. 6A and 6B show an exploded view of waveguide assembly 500,illustrating additional details of the waveguide assembly 500 inaccordance with the present disclosure. FIGS. 5A and 5B illustrate thecomponents of waveguide assembly 500 from opposite perspectives.

In accordance with the present disclosure, a portion of the waveguideassembly 500 may constitute the feed assembly 404. In some embodiments,the feed assembly 404 may include a dual-feed sub-assembly 404 acomprising a first dielectric insert 502 of a first feed 512 and asecond dielectric insert 504 of a second feed 514. The first and secondfeeds 512, 514 may be conjoined or otherwise mechanically connectedtogether. In some embodiments, the first and second dielectric inserts502, 504 may be conjoined along the reflector axis 402 a (FIG. 4).

The feed assembly 404 may further include a dual-port sub-assembly 404 bcoupled to or otherwise integrated with the dual-feed sub-assembly 404a. In some embodiments, the dual-port sub-assembly 404 b may includeportions of first feed 512 and second feed 514. The first dielectricinsert 502 may be part of the first feed 512 and, likewise, the seconddielectric insert 504 may be part of the second feed port 514. The firstfeed 512 may be configured for operation over a first frequency band. Insome embodiments, for example, the first feed port 512 may be configuredfor operation in the Ku band. The second feed 514 may be configured foroperation over a second frequency band. In some embodiments, forexample, the second feed 514 may be configured for operation in the Kaband.

In accordance with the present disclosure, a portion of the waveguideassembly 500 may constitute the support member 414, integrated with thefeed assembly 404 to support the feed assembly 404. In accordance withthe present disclosure, the support member 414 may comprise a first pairof waveguides 522 of first feed 512 and a second pair of waveguides 524of second feed 514 and partially encircled by the first pair ofwaveguides 522. As will be explained in more detail below, the first andsecond pairs of waveguides 522, 524 may couple to the waveguidecomponents 406 (FIG. 4) for propagation of signals between the first andsecond feeds 512, 514 and the RF section 408 (FIG. 4).

In the illustrated embodiment, the waveguide assembly 500 is a layeredstructure. In some embodiments, for example, the waveguide assembly 500may comprise a housing 506 comprising a first housing layer 506 a and asecond housing layer 506 b. The view in FIG. 6A shows interior detailsof the first housing layer 506 a, while opposite view in FIG. 6B showsinterior details of the second housing layer 506 b. The waveguideassembly 500 may include a septum layer 508 disposed between the firsthousing layer 506 a and the second housing layer 506 b.

In some embodiments, the housing 506 may define the first feed 512 and asecond feed 514. For example, the first feed 512 may comprise a firstport chamber 542 a (FIG. 6A) formed in the first housing layer 506 a anda second port chamber 542 b (FIG. 6B) formed in the second housing layer506 b. The first feed 512 may further include a first septum polarizer582 formed in the septum layer 508. The first septum polarizer 582 maybe disposed between the first and second port chambers 542 a, 542 b.Likewise, the second feed 514 may comprise a first port chamber 544 a(FIG. 6A) formed in the first housing layer 506 a and a second portchamber 544 b (FIG. 6B) formed in the second housing layer 506 b. Thesecond feed 514 may further include a second septum polarizer 584 formedin the septum layer 508. The second septum polarizer 584 may be disposedbetween the first and second port chambers 544 a, 544 b of the secondfeed 514. In the illustrated embodiment, the first septum polarizer 582and second septum polarizer 584 may be co-planar.

In some embodiments, the housing 506 may define the first pair ofwaveguides 522 and the second pair of waveguides 524 that comprise thesupport member 414. For example, the first pair of waveguides 522 maycomprise a first waveguide 522 a (FIG. 6A) formed in the first housinglayer 506 a and a second waveguide 522 b (FIG. 6B) formed in the secondhousing layer 506 b. Similarly, the second pair of waveguides 524 maycomprise a first waveguide 524 a (FIG. 6A) formed in the first housinglayer 506 a and a second waveguide 524 b (FIG. 6B) formed in the secondhousing layer 506 b.

The first waveguide 522 a of the first pair of waveguides 522 and thefirst waveguide 524 a of the second pair of waveguides 524 formed in thefirst housing layer 506 a may be separated by a wall 526 a formed in thefirst housing layer 506 a. Likewise, the second waveguide 522 b of thefirst pair of waveguides 522 and the second waveguide 524 b of thesecond pair of waveguides 524 formed in the second housing layer 506 bmay be separated by a wall 526 b formed in the second housing layer 506b. In some embodiments, the walls 526 a, 526 b may be co-planar orotherwise aligned.

The septum layer 508 may comprise a first portion 508 a and a secondportion 508 b. The first portion 508 a may constitute a wall thatseparates the first and second waveguides 522 a, 522 b of the first pairof waveguides 522. Similarly, the second portion 508 b may constitute awall that separates the first and second waveguides 524 a, 524 b of thesecond pair of waveguides 524. In some embodiments, the wall thatseparates the first and second waveguides 522 a, 522 b and the wall thatseparates the first and second waveguides 524 a, 524 b may be co-planar.

A surface 586 a (FIG. 6A) of the septum layer 508 may constitute acommon wall (surface) shared by the first waveguides 522 a, 524 a.Likewise, a surface 586 b (FIG. 6B) of the septum layer 508 mayconstitute a common wall shared the second waveguides 522 b, 524 b.

In some embodiments, the housing 506 may include a leading edge 506 chaving an ogive shape to mitigate generation of side lobe levels insignals reflected from reflector 402 (FIG. 4). In accordance with thepresent disclosure, a trailing edge 506 d of housing 506 may be flat inorder to remain within the sweep volume (422, 424, FIG. 4B) defined bythe reflector 402.

The housing 506 may include interface flanges 532 a, 532 b, 534 a, 534 bfor connecting to waveguides. For example, interface flanges 532 a, 532b may be connected to waveguides (not shown) for propagating signals infirst pair of waveguides 522. Likewise, interface flanges 534 a, 534 bmay be connected to waveguides (not shown) for propagating signals insecond pair of waveguides 524. Waveguide examples are provided below.

FIGS. 7A and 7B show details of dual-feed sub-assembly 404 a inaccordance with some embodiments of the present disclosure. In someembodiments, for example, the dual-feed sub-assembly 404 a may beconstructed by conjoining the first feed 512 and the second feed 514.For example, the dual-feed sub-assembly 404 a may comprise a housing 600having a unibody design that contains the first and second feeds 512,514. The housing 600 may comprise a first axially corrugated horn havinga first annular channel 602 integrated with second axially corrugatedhorn having a second annular channel 604. The profile view of FIG. 6Billustrates this more clearly. The housing 600 may be any suitablematerial used in the manufacture of antennas; e.g., brass, copper,silver, aluminum, their alloys, and so on.

The first feed 512 may comprise the first annular channel 602. The firstannular channel 602 may be defined by spaced apart concentric annularwalls 602 a, 602 b connected at one end by a bottom surface 602 c (FIG.7B). In some embodiments, the first feed 512 may include an outerdielectric annular member 612 that fits between the annular walls 602 a,602 b of the first annular channel 602. The dielectric annular member612 may improve a cross-polarization characteristic of the first feed512. Axial alignment of the dielectric annular member 612 may becontrolled by the depth of the bottom 602 c of the first annular channel602, acting as a stop. In some embodiments, the inside surface of theannular wall 602 a may be corrugated to further improvecross-polarization characteristics of the first feed 502 to controlillumination of the reflector 402 (FIG. 4).

The first feed 512 may further include a circular waveguide 622 definedby the inner annular wall 602 b of the first annular channel 602. Theinterior region of the circular waveguide 622 may receive a dielectricinsert 632 that extends forward beyond the opening of the circularwaveguide 622 and rearward into an interior region of the circularwaveguide 622. In some embodiments, a rear portion 632 a of thedielectric insert 632 may extend into a transition region 702 b (FIG.8A) of the dual-port subassembly 404 b. In some embodiments, thedielectric insert 632 may have a taper or conical profile that tapers inthe forward direction and in the rearward direction. The dielectricinsert 632 may improve matching to free space and illumination of thereflector 402 (FIG. 4).

The second feed 514, likewise, may comprise the second annular channel604. The second annular channel 604 may be defined by spaced apartconcentric annular walls 604 a, 604 b connected at one end by a bottomsurface 604 c (FIG. 7B). In some embodiments, the second feed 514 mayinclude an outer dielectric annular member 614 that fits between theannular walls 604 a, 604 b of the second annular channel 604. Thedielectric annular member 614 may improve a cross-polarizationcharacteristic of the second feed 514. Axial alignment of the dielectricannular member 614 may be controlled by the depth of the bottom 604 c ofthe second annular channel 604, acting as a stop. In some embodiments,the inside surface of the annular wall 604 a may be corrugated tofurther improve cross-polarization characteristics of the second feed514 to control illumination of the reflector 402 (FIG. 4).

The second feed 514 may further include a circular waveguide 624 definedby the inner annular wall 604 b of the second annular channel 604. Theinterior region of the circular waveguide 624 may receive a dielectricinsert 634 that extends forward beyond the opening of the circularwaveguide 624 and rearward into an interior region of the circularwaveguide 624. In some embodiments, a rear portion 634 a of thedielectric insert 634 may extend into a transition region 704 b (FIG.8A) of the dual-port subassembly 404 b, described in more detail below.In some embodiments, the dielectric insert 634 may have a taper orconical profile that tapers in the forward direction and in the rearwarddirection. The dielectric insert 634 may improve matching to free spaceand illumination of the reflector 402 (FIG. 4). The material for thedielectric inserts 632, 634 may be a plastic such as Rexolite® plasticor Ultem® plastic. In a particular implementation, the dielectricmaterial used for the dielectric inserts 632, 634 is a TPX® plastic.

The use of dielectric components, namely dielectric annular members 612,614 and dielectric inserts 632, 634, in the construction of thedual-feed sub-assembly 404 a allows for a reduction in the size ofhousings 602, 604 and circular waveguides 622, 624. In some embodiments,where the reflector 402 has a small F/D (e.g., 0.32), the illuminationbeam should be broad in order to adequately illuminate the reflector402. The reduced design size of the circular waveguides 622, 624 enabledby the dielectric components allows for the generation of a broadillumination beam. In some embodiments, the use of the dielectriccomponents can improve free space impedance matching of the circularwaveguides 622, 624 to improve signal propagation. In some embodiments,the dielectric components may provide some degrees of freedom to controlthe illumination of the reflector.

FIG. 7B illustrates additional details of the dual-feed sub-assembly 404a. For example the housing 600 may include respective stops 642, 644 tocontrol the axial alignment of the dielectric inserts 632, 634 duringmanufacture. In some embodiments, for example, the stops 642, 644 may bemachined into the housing 600. In some embodiments, O-rings 662 and 664may be used to retain respective dielectric inserts 632, 634 in positionwithin the housing 600.

FIG. 7B further shows the alignment of the dual-feed sub-assembly 404 arelative to the reflector axis 402 a in accordance with someembodiments. In some embodiments, the first and second annular channels602, 604 may both be aligned relative to the reflector axis 402 a suchthat the pointing direction 502 a of the first feed 502 will be off-axiswith respect to the reflector axis 402 a and the pointing direction 504a of the second feed 504, likewise, will be off-axis with respect to thereflector axis 402 a.

The embodiment illustrated in FIGS. 7A and 7B comprises a housing 600having a unibody design. It will be appreciated that in otherembodiments, the first feed 512 may a first housing (not shown) that isseparate from a second housing (not shown) that comprises the secondfeed 514. The first and second housings may be mechanically connected orotherwise arranged together to construct the dual-feed subassembly 404a.

The discussion will now turn to a description of the dual-portsub-assembly 404 b. FIG. 8A illustrates a profile view of the dual-portsubassembly 404 b (FIG. 6A). In accordance with the present disclosure,the first feed 512 and the second feed 514 of the dual-port subassembly404 b may be defined by the waveguide assembly housing 506. For example,the first feed 512 may comprise a common waveguide section 702 definedby a portion of the housing 506. The second feed 514, likewise, maycomprise a common waveguide section 704 defined by a portion of thehousing 506. The first feed 512 may include H-plane waveguide bends 712a, 712 b, defined by housing 506, to connect the first and secondwaveguides 522 a, 522 b of the first pair of waveguides 522 torespective portions of the common waveguide section 702. The septumpolarizer 582 may be convert a signal between one or more polarizationstates in the common waveguide section 702 and two signal components inthe individual waveguides 522 a, 522 b that correspond to orthogonalbasis polarizations (e.g., left hand circularly polarized (LHCP)signals, right hand circularly polarized (RHCP) signals, etc.). Thesecond feed 514 may likewise include H-plane waveguide bends 714 a, 714b, defined by housing 506, to connect the first and second waveguides524 a, 524 b of the first pair of waveguides 524 to the common waveguidesection 704. The septum polarizer 584 may be housed within the commonwaveguide section 704 to convert a signal between one or morepolarization states in the common waveguide section 704 and two signalcomponents in the individual waveguides 524 a, 524 b that correspond toorthogonal basis polarizations.

FIG. 8B depicts a perspective view of the first feed 512, illustratingadditional details of the first feed 512. It will be understood that thesecond feed port 514 may have a similar details. FIG. 8B more clearlyshows the integration of the first and second waveguides 522 a, 522 bwith respective H-plane waveguides 712 a, 712, and the integration ofthe H-plane bend 712 a, 712 with the common waveguide section 702. Theseptum layer 508 may constitute a common wall between the first andsecond waveguides 522 a, 522 b and between the H-plane bends 712 a, 712.

In accordance with embodiments of the present disclosure, the commonwaveguide section 702 may comprise a rectangular region 702 a and atransition region 702 b. The transition region 702 b may provide atransition from the rectangular waveguide of rectangular region 702 a toa circular waveguide to correspond to the circular waveguide in thedual-port sub-assembly 404 a, defined by the annular wall 602 b. Asshown in FIG. 7B, the transition region 702 b may have a decreasingdimension as the shape of the waveguide transitions from rectangular tocircular.

FIG. 9 illustrates directions of radiation using an antenna 400 inaccordance with the present disclosure. In some embodiments, the feedassembly 404 may directly illuminate the reflector 402. The pointingdirections 502 a, 504 a, respectively, of the first and second feeds502, 504 may be offset with respect to the reflector axis 402 a. In aparticular embodiment, for example, the pointing direction 502 a of thefirst feed 502 may lie above the reflector axis 402 a. Accordingly, asignal of maximum gain in a first frequency band (e.g., Ku band) maypropagate in a beam direction 802 below the reflector axis 402 a. Merelyas an example, the elevation beam squint may be −3.98° in a givenembodiment. Conversely, the pointing direction 504 a of the second feed504 may lie below the reflector axis 402 a. Accordingly, a signal ofmaximum gain in a second band (e.g., Ka band) may propagate in adirection 804 above the reflector axis 402 a. Merely as an example, theelevation beam squint may be +2.75° in a given embodiment. Additionalfeeds (e.g., Q-band or V/W-Bands) may also be located above or below thereflector axis 402 a and produce a corresponding beam direction on theopposite side of reflector axis 402 a. The location of the feedsrelative to the reflector axis is design choice and among the choicescan be to locate one feed on the reflector axis or nearer to the axisfor a higher frequency band, for example.

FIG. 10 shows examples, in accordance with the present disclosure, ofthe waveguides depicted in FIG. 3. Waveguides 312L and 312R in FIG. 3,for example, may be embodied as diplexers 912L and 912R, respectively.Diplexer 912L, for example, may couple the feed assembly 500 (e.g., atinterface flange 532 b) to the input and output ports of the transceivermodule 482 for LHCP signals. Likewise, diplexer 912R may couple the feedassembly 500 (e.g., at interface flange 532 a) to input and output portsof the transceiver module 482 for RHCP signals. Likewise, waveguides314L and 314R in FIG. 3 may be embodied as diplexers 914L and 914R,respectively. Diplexer 914L, for example, may couple the feed assembly500 (e.g., at interface flange 534 b) to an input port of transceivermodule 486 (e.g., FIG. 4) and to an output port of power amp 484 forLHCP signals. Likewise, diplexer 914R, for example, may couple the feedassembly 500 (e.g., at interface flange 534 a) to an input port oftransceiver module 486 (e.g., FIG. 4) and to an output port of power amp484 for RHCP signals. FIG. 3 shows bandpass filters 336 a, 336 b. FIG. 9shows an example of a bandpass filter waveguide at 916L configured toconnect the output of the first transceiver module 482 to the poweramplifier module 484.

FIG. 11A shows additional details of diplexer 912L in accordance withthe present disclosure. It will be understood that the diplexer 912R mayhave a similar, but mirror-imaged, structure. In some embodiments,diplexer 912L may comprise three waveguide segments 902, 904, 906.Waveguide segment 902 may include a port 902 a for coupling to an output(tx) port of the first transceiver module 482 (FIG. 4). An E-plane bend902 b may connect the port 902 a to a 90° H-plane bend 902 c. TheE-plane bend 902 b allows for the waveguide segment 902 to remain closeto the packaging of the first transceiver module 482 to maintain a smallpackage outline 412 a (FIG. 4A). The H-plane bend 902 c may connect to afilter 902 d. In some embodiments, for example, filter 902 d may be abandpass filter to filter signals to be transmitted to control out ofband emissions.

Waveguide segment 904 may include a port 904 s for coupling to an input(rx) port of the first transceiver module 482. An E-plane bend 904 b mayconnect the port 904 a to a filter 904 c, while keeping the waveguidesegment 904 close to the packaging of the first transceiver module 482.The filter 904 c may be a low pass filter to filter received signals.The filter 902 d may connect to filter 904 c to combine the twowaveguide segments 902, 904.

Waveguide segment 906 is a common waveguide to carry signals thatpropagate in waveguide segments 902, 904. Waveguide segment 906 maycomprise an H-plane bend (e.g., 60° bend) coupled to the filter 904 c.An E-plane bend 906 b allows the waveguide segment 906 to stay close tothe packaging of the first transceiver module 482 while allowing for thewaveguide to be routed to the waveguide assembly 500. The waveguidesegment 906 may include a waveguide width reduction segment 906 cconnected to an H-plane bend 906 d. The waveguide segment 906 mayinclude a waveguide height reduction segment with an E-plane bend 906 ethat terminates at port 906 f. The port 906 f may couple to thewaveguide assembly 500 (FIG. 5A), for example, at interface flange 532 bof the waveguide assembly 500.

In accordance with the present disclosure, the H-plane bends 902 c, 906a, 906 d may allow the diplexer 912L to be routed among ports 902 a, 904a, 906 f while keeping the routing area small. The E-plane bends 902 a,904 a, 906 b, 906 e may allow the diplexer 912L to maintain a lowprofile within the package outline 412 a of the RF & waveguide package412 (FIG. 5A).

FIG. 11B shows additional details of diplexer 914L in accordance withthe present disclosure. It will be understood that the diplexer 914R mayhave a similar, but mirror-imaged, structure. In some embodiments,diplexer 914L may comprise three waveguide segments 922, 924, 926.Waveguide segment 922 may include a filter 922 a. In some embodiments,for example, filter 922 a may be a high pass filter to filter signals tobe transmitted and control out of band emissions. The filter 922 a maycouple to an H-plane U-bend 922 b in order to minimize the diplexerrouting area. The H-plane U-bend 922 b may couple to an E-plane bend 922c. The E-plane bend 922 c, in turn, may terminate at port 922 d, whichmay couple to an output (transmit) port of the power amplifier module484 to receive signals for transmission.

Waveguide segment 924 may include filter 924 a. In some embodiments,filter 924 a may be a low pass filter to filter received signals. Thefilter 924 a may couple to an H-plane U-bend 924 b in order to minimizethe diplexer routing area. An E-plane bend 924 c may be coupled to theplane U-bend 924 b and terminate at a port 924 d. The port 924 d maycouple to an input (rx) port of the second transceiver module 486 (FIG.4) to receive signals from the second transceiver module 486.

Waveguide segment 926 may include a common waveguide 926 a that thefilters 922 a and 924 a couple to. The common waveguide 926 a may coupleto an E-plane bend 926 b, which terminates at port 926 c. The port 926 cmay couple to the waveguide assembly 500 (FIG. 5A), for example, atinterface flange 534 b of the waveguide assembly 500.

As noted above, in accordance with the present disclosure, the H-planebends 922 b, 924 b may allow the diplexer 914L to be routed among theports 922 c, 924 c, 926 c while maintaining a small routing footprint.The E-plane bends 922 c, 924 c, 926 b may allow the diplexer 914L tomaintain a low profile within the package outline 412 a of the RF &waveguide package 412 (FIG. 5A).

FIG. 11C shows additional details of bandpass filter waveguide 916L. Insome embodiments, the bandpass filter waveguide 916L may include ports932 a, 932 b. Port 932 a may couple to an output of the secondtransceiver module 482. Port 932 b may couple to an input of the poweramplifier module 484. The bandpass filter waveguide 916L may include acombination of H-plane bends 946 and E-plane bends 948 to connect theports 932 a, 932 b to filter 934. The H-plane bends 936 may allow thebandpass filter waveguide 916L to be routed between the firsttransceiver module 482 and the power amplifier module 484 with a smallrouting area. The E-plane bends 936 and 938 may allow the bandpassfilter waveguide 916L to maintain a low profile within the packageoutline 412 a of the RF & waveguide package 412 (FIG. 5A).

The above description illustrates various embodiments of the presentdisclosure along with examples of how aspects of the particularembodiments may be implemented. The above examples should not be deemedto be the only embodiments, and are presented to illustrate theflexibility and advantages of the particular embodiments as defined bythe following claims. Based on the above disclosure and the followingclaims, other arrangements, embodiments, implementations and equivalentsmay be employed without departing from the scope of the presentdisclosure as defined by the claims.

What is claimed is:
 1. An antenna comprising: a single reflector; awaveguide assembly having a feed assembly and a support member, whereinthe support member extends from a location behind the single reflectorto orient the feed assembly for direct illumination of the singlereflector, wherein the support member has an arcuate shape and a leadingedge along the arcuate shape that is oriented towards the singlereflector, the leading edge having a tapered cross-section, and whereinthe waveguide assembly comprises: a first housing layer comprising afirst waveguide of a pair of waveguides coupled to a first portion of acommon waveguide of the feed assembly; a second housing layer comprisinga second waveguide of the pair of waveguides coupled to a second portionof the common waveguide; and a septum layer between the first housinglayer and the second housing layer, the septum layer comprising a septumpolarizer coupled between the common waveguide and the pair ofwaveguides.
 2. The antenna of claim 1, wherein the first waveguidecorresponds to a first polarization, and the second waveguidecorresponds to a second polarization.
 3. The antenna of claim 1, furthercomprising a positioning system to point the antenna.
 4. The antenna ofclaim 1, wherein the septum layer forms surfaces of the first and secondwaveguides of the pair of waveguides.
 5. The antenna of claim 1, whereinthe tapered cross-section has an ogive shape.
 6. The antenna of claim 1,wherein the tapered cross-section mitigates scattering interactionbetween the support member and the single reflector.
 7. The antenna ofclaim 1, wherein the support member is within a swept volume of thesingle reflector.
 8. The antenna of claim 1, wherein the singlereflector has an edge that is non-circular.
 9. The antenna of claim 1,wherein the support member extends through an opening of the singlereflector.
 10. The antenna of claim 9, wherein the opening is at aperiphery of the single reflector.
 11. The antenna of claim 1, whereinthe feed assembly comprises a dielectric insert within the commonwaveguide and extending beyond an opening of the common waveguide. 12.The antenna of claim 11, wherein the dielectric insert extends into atransition region of the common waveguide, wherein the transition regiontransitions between a rectangular waveguide and a circular waveguide andhas a decreasing dimension.
 13. The antenna of claim 1, wherein thesupport member has a trailing edge oriented away from the singlereflector having a different cross-section than the leading edge. 14.The antenna of claim 13, wherein the trailing edge has a flatcross-section.
 15. The antenna of claim 1, wherein: the first housinglayer further comprises an interface flange for the first waveguide thatis behind the single reflector; and the second housing layer furthercomprises an interface flange for the second waveguide that is behindthe single reflector.
 16. The antenna of claim 15, further comprisingradio frequency (RF) electronics and a system of waveguides that couplethe RF electronics to the interface flanges for the first and secondwaveguides of the pair of waveguides.
 17. The antenna of claim 16,wherein the waveguide assembly, the RF electronics, and the system ofwaveguides are arranged within a swept volume of the single reflector.18. The antenna of claim 16, wherein the system of waveguides includesone or more filters.
 19. The antenna of claim 16, wherein the system ofwaveguides includes a first diplexer coupled to the first waveguide, anda second diplexer coupled to the second waveguide.
 20. The antenna ofclaim 19, further comprising a transceiver having a first input port anda first output port coupled to the first diplexer, and having a secondinput port and a second output port coupled to the second diplexer.